Mobile material mixers and agitators, particularly concrete mixers and agitators



April 14, 1964 W. CUNNINGHAM MOBILE MATERIAL MIX Filed Feb. 9, 1960 ERS AND AGIIATORS, PARTICULARLY CONCRETE MIXERS AND AGITATORS 4 Sheets-Sheet 1' //v vs A/Tok W191 L BC E CUNNINGIIIIM mnsoN, K l-EHNHINEM RHTHBUR/Y 1! W5 A TTORNEIS A ril 14, 1964 3,128,631 S. PARTICULARLY ATORS W. CUNNINGHAM MOBILE MATERIAL MIXERS AND AGITATOR CONCRETE MIXERS AND AGIT 4 Sheets-Sheet 2 //\/VENTOR Filed Feb. 9, 1960 MHSo/V. h OLEHMBIN EN, fiI/iTHB 0/2 14 w y 55 ATTORNEY Aprll 14, 1964 w CUNNINGHAM 3,128,631

- MOBILE MATERIAL MIXERS AND AGITATORS, PARTICULARLY CONCRETE MIXERS AND AGITATORS Filed Feb. 9, 1960 4 Sheets-Sheet 3 Fig .4.

M/l ENTOR w/umcE cuN/Y/IYGHfiM nasolv, HoLEHNfiI/YEN, RfiT/IBUR/V as u! yss 'ATTORNEYQ A ril 14, 1964 w. CUNNINGHAM 3,128,631

MOBILE MATERIAL MIXERS AND AGITATQRS, PARTICULARLY CONCRETE MIXER-S AND AGITATORS 4 Filed Feb. 9, 1960 4 Sheets-Sheet 4 IN VEN TOR WBLLQCE CUIVIVHVGHHM L m EFT/I801? a wyss 93 K0 EHMH EN, ATTORNEX? United States Patent Ofiice MGBILE MATERIAL MIXERS AND AGITATSRS,

YARTICULAJRLY CONCRETE MIXERS AND AGI- TATGRS Wallace Cunningham, Chatham, England, assignor to Winget Limited, Rochester, Kent, England Filed Feb. 9, 1960, Ser. No. 7,719 1'7 Qlaims. (Cl. 74-4584) The present invention is concerned with material mixers and agitators which are carried upon vehicles, and particularly to concrete mixers and agitators. Hereinafter, wherever the context admits, all such mixers and agitators will be referred to as concrete mixers.

In some machines used for transporting concrete from central mixing stations to the sites, a container, which is essentially the same as a concrete mixer, is mounted on the chassis of a self-propelled vehicle and the container is rotated at low speed so that the concrete being transported in the vehicle is agitated to prevent it setting or segregating.

As the power required is low, it has become common practice to derive the power for rotating the drum or container from a power take-oif mechanism attached to the vehicle gear box.

The driven gear of the power take-off mechanism meshes with a gear on the layshaft of the vehicle gearbox so that the drum is energised by the vehicle engine and clutch and therefore the position of the gears in the vehicle gearbox makes no difference to the drum drive. Further, when the drive to the drum is engaged, the back axle and the drum are interconnected except when the vehicle gear box is in neutral, this latter condition not being affected by the position of the vehicle clutch.

Methods of arranging the drive from the power takeoff (driven from the gear box) to the drum vary, but commonly consist of (a) A single speed drive by means of a reduction gear box with chain, belt and/or gears and with or without an auxiliary clutch between the power take-off and the drum;

(b) As in (a), but with the reduction gear box arranged to provide two speeds and the auxiliuy clutch mounted between the power take-off and the two-speed box;

As in (b) but with a reversing gear provided either in conjunction with the two speed box or incorporated in the power take-off; and

(d) Any combination of (a), (b) and (c).

In order to operate the auxiliary clutch referred to above it is usual to provide for its direct control (independently of the vehicle clutch) adjacent to the operation of the change speed lever and to interconnect the operation of the auxiliary and the vehicle clutch.

The direct operation of the auxiliary clutch is to enable the speed of the drum tobe altered thus providing in case (0) referred to above a fast speed for charging the drum and a slow speed for agitating the concrete and when the drive is reversed a low and a fast speed for discharging the concrete.

The interconnection of the two clutches serves two main purposes, namely:

(1) To take the drum load off the lay shaft or drive shaft when the brakes are applied; and

(2) To take the drum load off the lay shaft when changing gears.

It is not an essential to take the drum load off the lay shaft when the brakes are applied but it is of great assistance to the driver and aids the braking of the vehicle in emergency stops.

In the case of a crash type vehicle gearbox it is not essential to take the drum load off the layshaft when Patented Apr. 14., L964 changing gear but removing the drum load from the layshaft assists the driver to synchronise the gears when double clutching.

An auxiliary clutch is essential when the vehicle has a syncro-mesh gearbox, since the synchronizing devices are not designed to overcome the load that the drum puts on the layshaft when changing the vehicle speed.

When the auxiliary clutch is mechanically operated it is spring-loaded when engaged and the interconnection with the vehicle clutch means that the driver has an added load to overcome when depressing the clutch pedal. Since the majority of the machines referred to are used in built-up areas the added load is very tiring.

If the auxiliary clutch is operated centrifugally, the speed change for the drum must be brought into the drivers cab or two men are required to change the drum speed i.e., one to depress the vehicle clutch and one to operate the change speed lever.

The object of the present invention is to overcome the aforementioned disadvantages.

With the above object in view, according to the invention we provide a concrete mixer which is carried upon a vehicle and which comp-rises a mixing drum driven from a power take-off in the vehicle gear box by a transmission which comprises an electro-magnetic clutch or other coupling means which, through appropriate wiring and controls can be independently operated or, alternatively, interconnected with the vehicle clutch.

According to a further feature of the invention the concrete mixer comprises a mixing drum driven from a power take-oif in the vehicle gear box by a transmission which comprises a switch-controlled electro-magnetic clutch or coupling which receives electric power from a power source through a switch which is manually controlled or, alternatively, through an additional switch which is interconnected with the vehicle clutch operating mechanism, such that when the vehicle clutch pedal is depressed the electro-magnetic' clutch or other coupling .means and the vehicle clutch are both disengaged simultaneously or with a time lag between the operation of the electromagnetic clutch or other coupling means and the vehicle clutch.

The concrete mixer may comprise an electro-magnetic clutch including a driving member which is interconnected to a driven member on the mixing drum and which rotates freely when the clutch is not energised but which is rotated when the clutch is energised and thus causes the driven member and the drum to rotate. The driving and driven members may be interconnected through a drum-drive gear box.

In a convenient constructional'form of the invention the said driving member consists of a chain sprocket which is freely rotatable upon a shaft which is rotated by a power take-01f in the vehicle gear box and to which the magnetic clutch is fixed. The chain sprocket is connected by a chain to a second chain sprocket fixed on the main or input shaft of the drum-drive gear box and the output shaft of the latter-is operatively connected to the mixing drum. The drum-drive gear box is preferably controlled by a manually-operated gear lever assembly.

A modification of the construction referred to above and further constructional features of the invention will be described hereinafter.

Two constructional forms of the invention, both applied to a concrete mixer carried upon a vehicle, are hereinafter described, by Way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of part of the vehicle and the concrete mixer mounted thereon;

FIGURE 2 is an enlarged view of the electro-magnetic clutch or coupling assembly and FIGURE 1 and also shows the chain sprocket which is driven by a chain from a chain sprocket included in the clutch or coupling assembly and which is fixed to the input or main shaft of the drum-drive gear box;

FIGURE 3 is adiagrammatic sectional view of the elcctro-magnetic clutch or Coupling assembly;

FIGURE 4 is a sectional elevation of a ferro-magnetic .particle clutch which is used in a modification of the construction shown in FIGURES 1 to 3;

FIGURE is also an elevation, partly in section, corresponding to FIGURE 4 and showing the connection of the input shaft of the clutch to the vehicle gear box and the connection of the output shaft of the clutch to the input shaft of the drum drive gear box; and

FIGURE 6 is a diagram showing one example of a wirin g circuit.

Referring to FIGURES 1 to 3:

In this constructional form of the invention the concrete mixing drum 1 is mounted in known manner upon the main frame 2a of a motor driven vehicle or vehicle means 2 behind the drivers cab 3. As is known, the vehicle 2 is provided with a conventional motor or motor means 2b which drives a plurality of devices including the vehicle 2, through a clutch or clutch means 2c, transmission 2d, and drive shaft 2e; and the drum 1, in a manner hereinafter more fully described. The axis of rotation of the drum is inclined to the horizontal, the charging end of the drum being uppermost. Also in known manner the drum is rotated through a drum-driving pinion 5 which engages with a bevel wheel 6 fixed to the closed end of the drum, the pinion being mounted on a drum-drive gear box output shaft 7 which will be referred to hereinafter.

A magnetic clutch or clutch means 8 is also carried by the main frame, below'the level of the said pinion 5, on a bracket 9 which can be adjusted vertically. The magnetic clutch assembly comprises a shaft 10, FIG. 2, which is turnably supported at its front and rear ends in bearings 11 and 12, the front end of the shaft being fitted with a coupling flange 13 which is fixed to a coupling flange 14, FIG. 1, forming part of a universal joint 15 arranged at the end of a cardan shaft 16, the front end of which latter is connected by another universal joint 17 to a power takeoff shaft 18 driven by the vehicle gearbox 2d, also referred to as a transmission or transmission gear means.

The electro-magnetic clutch may be of any known construction, and a suitable clutch is shown diagrammatically in FIGURE'3. This clutch comprises a hub part 20 in which there is taperlock bush 21 in which the shaft 10 is fixed by a key 22 shown in FIGURE 2. The clutch comprises an electro-magnet 23, a brush holder 24, a collector ring 25 and an armature member 26. As shown in FIG. 2, the hub 27 of a chain sprocket 28 is rotatably mounted upon the shaft 10 by means of axially-spaced ball bearings 29 and 30, the arrangement being such that when the magnetic clutch is not energised the sprocket can rotatefreely on the shaft. The hub 27 is fixed to the armature 26"of the clutch by means of angularly-spaced pins 31 carried by the armature and the sprocket is connected by means of a chain 32, FIG. 1, to a chain sprocket 33 fixed on the main shaft 34 of a drum-drive gearbox 35 which is mounted on the main frame 2 of the vehicle behind the cab 3 and the gears of which are controlled by a handoperated control lever 36. By interconnection of the electro-magnetic clutch switch with the vehicle clutch pedal 2]" the magnetic clutch can be controlled by the vehicle clutch pedal 2 with negligible additional effort when the pedal is depressed. The electro-magnetic clutch may also be controlled by a manual control 37, FIG. 1, which actuates a rotary switch in series with the abovementioned switch and thus permits the electro-magnetic clutch to be engaged or disengaged from a position outside the cab of the vehicle. The clutch receives its energy from the vehicle battery and when it is energised the armature 26 is rotated and, through the pins 31, causes the sprocket 28, the sprocket 33 and the gearbox main shaft 34to rotate.

When a vehicle clutch 2c is being engaged through a clutch pedal 2} the electro-magnetic clutch can be delayed by increase of the resistance in the electrical circuit, whereby the torque capacity can be varied, thus varying the period of slip which will take place in the clutch before the gearbox main shaft comes to rest. The purpose of this is that due to the concrete charge in it the drum 1 is out of balance, so that if the vehicle gear change has been slow the drum 1 may be at rest or rotating in the reverse direction or when the vehicle 2 is stopped in traffic with the vehicle clutch 2c disengaged the drum will be at rest. Delay in engagement of the electro-rnagnetic clutch 8 enables the vehicle transmission 2d to be energised before the drum load is transmitted to the engine.

In some versions of the machines with which the invention is concerned a brake is fitted to hold the drum in any required position and/or to prevent the drum reversing whilst changing speed or when the vehicle is at rest. These purposes can be achieved by fitting an electro-magnetic brake operated by interconnection with and/or independently of the electromagnetic clutch.

As an alternative to the electro-magnetic clutch used in the construction shown in FIGURES 1 to 3, the clutch may be replaced by a ferro-magnetic particle clutch of known construction and operation; for example, as shown in FIGURES 4 and 5 and indicated generally by the reference numeral 40. Such a clutch comprises a casing 41 wherein an input shaft 45 is turnably mounted in spaced ball bearings 43 and 44 and an output shaft 42 is turnably mounted in spaced ball bearings 46 and 47. An output rotor 50, having a bulbous rim 50A, is secured to a flange 42A on the output shaft 42. An input rotor 48 having a peripheral rim 49 and carrying a disc 48A is fixed to the flanged inner end 45A of the shaft 45, the disc being turnable around the flange 42A. An air gap is left between the peripheral surface 53 of the rim 50A of the output rotor 50 and the inner surface of the rim 49 and a ferromagnetic powder material 55 is arranged in the air gap. The clutch also comprises a stationary exciting coil 56.

As in the construction shown in FIGURES 1 to 3, the input shaft 45 is connected to a power take-off shaft (not shown) driven by the vehicle gear box through a universal joint 56, FIG. 5, arranged at one end of a cardan shaft 57, the opposite end of which is connected to an output shaft in the vehicle gear box. A chain sprocket 58 is keyed on the output shaft42 and is connected by chains (not shown) to a chain wheel 59 keyed on the main shaft 60 of the drum drive gear box 35, see FIGURE 1.

As is known, the action of the ferromagnetic powder medium depends upon the magnetic flux density in the air gap between the peripheral surface of the rim 50A of the output rotor 50 and the inner surfaces of the rims 49 and '52.

When the exciting coil is energised and during the takeoff period the clutch operates smoothly and without jerk. During full excitation, the ferro-magnetic powder becomes solid and the input rotor is solidly connected with the output rotor, there is no slip, no generation of heat and no loss of efiiciency. The output shaft 42 of the clutch or coupling means is rotated and the main shaft 60 of the drum drive gear box is driven through the chain sprocket 58, the chain wheel 59 and the chains connecting the chain sprocket and the chain Wheel.

In brief, the only difference between the construction shown in FIGURES l to 3 and that shown in FIGURES 4 and 5 is the replacement of the electromagnetic clutch by the ferro-magnetic particle clutch.

When the vehicle is travelling, the speed of rotation of the mixing drum is generally about 2 r.p.m., whereas when the contents of the drum are being mixed or discharged the drum rotates at about 10 to 12 r.p.m. A convenient wiring diagram is shown in FIGURE 6. One side of the vehicle battery 62 is connected directly to the electromagnetic clutch 63 while the other side of the battery is connected to a mixing and agitating control switch 64, one contact A of which is connected through a switch 65, which is interlocked with the vehicle clutch pedal, and a resistance R to the other side of the clutch. The other contact B of the switch 64 is connected to the same side of the clutch 63 as the resistance R through a manually-operated rheostat 66 and a resistance R When the switch 64 is in the position A the current is passed through the resistance R and the maximum current is limited to such a value that the electro-magnetic clutch engages smoothly when the switch 65 is operated by the vehicle clutch pedal. When the switch 64 is in the position B, however, the mixing drum is caused to rotate by the manual operation of the rheostat 66, so that a larger current passes which is dependent upon the value of the resistance R to give the electro-magnetic clutch a torque capacity say 5 to 6 times greater than that in the previous condition. If, for example, the resistance R is set to give a torque t for agitating, the resistance R may be set to give a torque St for mixing and discharging.

I claim:

1. A vehicle comprising vehicle means, power driven means carried by said vehicle means, motor means for selectively driving said vehicle means and said power driven means, transmission gear means for interconnecting said motor means and said vehicle means, first clutch means interconnecting said gear means and said motor means for operatively engaging and disengaging said motor means and said gear means, power take-oif means from said gear means for driving said power driven means, transmission gear means interconnecting said power take-off means and said power driven means, second clutch means interconnecting said transmission means and said power take-off means for operatively engaging and disengaging said power take-off means and said power driven means, first actuating means for actuating said first clutch means, second actuating means interconnecting said first actuating means and said second clutch means for actuating said second clutch means in response to actuation to said first clutch means, and means independent of said second actuating means for independently actuating said second clutch means.

2. A vehicle is set forth in claim 1 above wherein said second clutch means comprises an electro-magnetic clutch.

3. A vehicle as set forth in claim 1 above wherein said' second clutch means comprises a ferro-magnetic particle clutch including a pair of rotors, a ferro-rnagnetic powder medium arranged '-'in an air gap between said pair of rotors, an exciting coil for creating a magnetic flux density in the air gap, the arrangement being such that under full excitation the rotors become solid and there is no slip between them.

4. A vehicle as set forth in claim 1 above wherein said vehicle means includes a vehicle cab and wherein the means for actuating said first clutch means is positioned within the cab and wherein said second actuating means is positioned outside of the cab.

S. A vehicle as set forth in claim 1 above wherein means are provided for actuating said second clutch means in predetermined time relation to said first clutch means.

6. A power unit for selectively driving a plurality of devices comprising motor means for selectively driving said devices, transmission gear means for interconnecting said motor means and one of said devices, clutch means interconnecting said transmission gear means and said motor means for operatively engaging and disengaging said motor means and said gear means, power take-off means from said gear means for driving another of said devices, transmission means interconnecting said power take-off means and said another of said devices, clutch means interconnecting said transmission means and said power take-off for operatively engaging and disengaging said power take-off and said another of said devices, means for actuating the first-mentioned clutch means, means for actuating said second-mentioned clutch means, and independent means interconnecting the last two-mentioned means for actuating said second-mentioned clutch means in response to actuation to said first mentioned clutch means.

7. A power unit as set forth in claim 6 above wherein the means for actuating the first-mentioned clutch and the means independent of said means for actuating the second-mentioned clutch means are positioned remote from each other.

8. A vehicle comprising vehicle means, power driven means carried by said vehicle, a motor carried by said vehicle for selectively driving said vehicle means and said power driven means, a transmission operatively connected to drive said vehicle means, a first clutch interconnecting said transmission and said motor, a second transmission connected to drive said power driven means, second clutch means interconnecting said second transmission and the first-mentioned transmission, means for actuating said first clutch, means for independently actuating said second clutch, and means interconnecting the last two-mentioned means for actuating said second-mentioned clutch in response to the actuation of'said first-mentioned clutch.

9. A vehicle as set forth in claim 8 above wherein the last-mentioned means includes means for delaying the actuation of said second-mentioned clutch with reference to the actuation of said first-mentioned clutch.

10. A power unit, a motor, a transmission, a first clutch interconnecting said transmission and said motor, a second transmission, a second clutch interconnecting said second transmission and the first-mentioned transmission, means for actuating said first clutch, means for independently actuating said second clutch, and means interconnecting the last two-mentioned means for actuating said second-mentioned clutch in response to the actu ation of said first-mentioned clutch.

11. In combination with a first drivable device, a second drivable device and motor means connectable to selectively drive said devices, the improvement comprising a first clutch adapted to be driven by said motor, a transmission driven by said clutch and adapted to drive one of said devices, a second clutch connected to said transmission, a second transmission driven by said second clutch and adapted to drive another of said devices, means for actuating said first clutch, means for actuating said second clutch independently of said first clutch, and means interconnecting the last two-mentioned means for actuation of one of said clutches in response to actuation of the other of said clutches.

12. A vehicle comprising vehicle means, a power driven means carried by said vehicle means, motor means, transmission gear means for interconnecting said motor means and said vehicle means, a first clutch interconnecting said transmission gear means and said motor means, power take-oil means associated with said transmission gear means, second transmission gear means operatively associated to drive said power driven means, an electrically controlled second clutch interconnecting the second transmission gear means and the power take-off, means for actuating said first clutch, electrical switch means for actuating said second clutch independently of said first clutch, and additional electrical switch means operatively associated with said means for actuating said first clutch means and electrically connected to control said second clutch in response to actuation of said first clutch.

13. A vehicle as set forth in claim 12 above wherein said additional electrical switch means is related to said means for actuating said first clutch to provide a delay in the actuation of the electrically controlled clutch with respect to the actuation of said first clutch.

14. The combination with a vehicle means which is carried upon a vehicle having a transmission gear box controlled by a vehicle clutch and which includes rotatable power driven means, the improvement comprising means for rotating the driven means, said means including a power take-off in the vehicle gear box and a transmission for operatively connecting said power driven means to said power take-01f, said transmission including a switch controlled electrically actuated clutch, an electric power source for supplying electric power to said electrically actuated clutch, a manually controllable switch for controlling the supply of electric power to said electrically actuated clutch, an additional switch for controlling the supply of electric power to said electrically actuated clutch independent of said first switch, means interconnecting the vehicle clutch with the additional switch for insuring that when the vehicle clutch pedal is depressed the electrically actuated clutch and the vehicle clutch are engaged and disengaged in predetermined time relation with each other.

15. A power unit for selectively driving a plurality of devices comprising motor means for selectively driving said devices, transmission gear means for interconnecting said motor means and one of said devices, clutch means interconnectingsaid transmission gear means and said motor means for operatively engaging and disengaging said motor means and said gear means, power takeoff means from said gear means-for driving another of said devices, transmission means interconnecting said power take-off means and said another of said devices, a ferro-magnetic particle clutch means interconnecting said transmission means and said power take-01f for operatively engaging and disengaging said power take-off and said other of said devices and including a driven member consisting of an input rotor and a driving member consisting of an output rotor, and a ferromagnetic powder medium arranged in an air gap between said rotors, and an exciting coil for creating a magnetic flux density in said air gap, the arrangement being such that under full excitation of said coil the rotors become solid and there is no slip between them, means for actuating the firstmentioned clutch means, means for actuating said second-mentioned clutch means, and independent means interconnecting the last two-mentioned means for actuating said second-mentioned clutch means in response to actuation tosaid first-mentioned clutch means.

16. A power unit for selectively driving a plurality of devices comprising motor means for selectively driving said devices, transmission gear means for interconnecting said motor means and one of said devices, clutch means interconnecting said transmission gear means and said motor means for operatively engaging and disengaging said motor means and said gear means, power takeofl? means from said gear means for driving another of said devices, transmission means interconnecting said power take-oi? means and said another of said devices,

clutch means interconnecting said transmission means and said power take-01f for operatively engaging and disengaging said power take-olI and said other of said devices, means for actuating the first-mentioned clutch means, means for actuating said second-mentioned clutch means, and independent means interconnecting the last two-mentioned means for actuating said second-mentioned clutch means in response to actuation to said firstmentioned clutch means in predetermined time relation relative to the first-mentioned clutch means in response to actuation of said first-mentioned clutch means.

17. A power unit for selectively driving a plurality of devices comprising motor means for selectively driving said devices, transmission gear means for interconnecting said motor means and one of said devices, clutch means interconnecting said transmission gear means and said motor means for operatively engaging and disengaging said motor means and said gear means, power take-01f means from said gear means for driving another of said devices, transmission means interconnecting said power take-01f means and said another of said devices, clutch means interconnecting said transmission means and said power take-01f for operatively engaging and disengaging said power take-01f and said other of said devices, means for actuating the first-mentioned clutch means, means for actuating said second-mentioned clutch means, and independent means interconnecting the last two-mentioned means for actuating said second-mentioned clutch means in response to actuation to said firstmentioned clutch means and including means for delaying the actuation of the second-mentioned clutch means with reference to actuation of the first-mentioned clutch means.

References Cited in the file of this patent UNITED STATES PATENTS 1,016,052 Webb Jan. 30, 1912 1,396,074 Stumpenhorst Nov. 8, 1921 2,068,579 Tatter Jan. 19, 1937 2,661,935 Willard Dec. 8, 1953 2,680,377 Gerst June 8, 1954 2,732,189 Gerst Jan. 24, 1956 2,741,130 Gerst Apr. 10, 1956 2,793,013 Mittelstadt et al May 21, 1957 2,818,148 Winther Dec. 31, 1957 2,862,632 Thurmond et al. Dec. 2, 1958 2,958,406 Pierce Nov. 1, 1960 

1. A VEHICLE COMPRISING VEHICLE MEANS, POWER DRIVEN MEANS CARRIED BY SAID VEHICLE MEANS, MOTOR MEANS FOR SELECTIVELY DRIVING SAID VEHICLE MEANS AND SAID POWER DRIVEN MEANS, TRANSMISSION GEAR MEANS FOR INTERCONNECTING SAID MOTOR MEANS AND SAID VEHICLE MEANS, FIRST CLUTCH MEANS INTERCONNECTING SAID GEAR MEANS AND SAID MOTOR MEANS FOR OPERATIVELY ENGAGING AND DISENGAGING SAID MOTOR MEANS AND SAID GEAR MEANS, POWER TAKE-OFF MEANS FROM SAID GEAR MEANS FOR DRIVING SAID POWER DRIVEN MEANS, TRANSMISSION GEAR MEANS INTERCONNECTING SAID POWER TAKE-OFF MEANS AND SAID POWER DRIVEN MEANS, SECOND CLUTCH MEANS INTERCONNECTING SAID TRANSMISSION MEANS AND SAID POWER TAKE-OFF MEANS FOR OPERATIVELY ENGAGING AND DISENGAGING SAID POWER TAKE-OFF MEANS AND SAID POWER DRIVEN MEANS, FIRST ACTUATING MEANS FOR ACTUATING SAID FIRST CLUTCH MEANS, SECOND ACTUATING MEANS INTERCONNECTING SAID FIRST ACTUATING MEANS AND SAID SECOND CLUTCH MEANS FOR ACTUATING SAID SECOND CLUTCH MEANS IN RESPONSE TO ACTUATION TO SAID FIRST CLUTCH MEANS, AND MEANS INDEPENDENT OF SAID SECOND ACTUATING MEANS FOR INDEPENDENTLY ACTUATING SAID SECOND CLUTCH MEANS. 